Freezing will split the two phases better indeed.
One way is to freeze in a beaker kind of recipient, closed with plastic and rubber band.
Then poor of the top layer (to be re-used) and use a paper towel to dry the frozen acid surface as much as possible, as soon as the watery layer is frozen. The paper towel gets little wet by sucking up remaining hydrocarbons. I've never done the IPA or acetone wash to work like the paper towel trick, I did not know of it until now (thanks!), but both tricks can be combined.
Option from there: boil the acid solution hard (adding some water now and then to remain level) to strip off hydrocarbons that found a way in there, until most (all) smell is gone. The steam bubbles coming from the bottom attract the hydrocarbons (due the ultra low partial pressure of hydrocarbons inside the steam bubbles, hence boil hard) and then take them up and out with the steam. Fume hood = On of course.
I've no idea how effective it is in absolute removal, but one can boil the smell out to large extend.
After that, evaporating, sod-carb...etc.. as said.
Toluene's solvability in water (0.5 g/l) > that of xylene (0.2 g/l).
IIRC, it has been posted that phosphoric acid is not the best for salting out due having multiple pKa's. I've never checked out how that plays a practical role, but the word was out and vinegar is such an easy alternative.
I've never found toluene smell as much like xylene does.
